The invention relates generally to a ceramic light construction element and for a process for making same.
Ceramics of lightweight construction materials are known. Typically such materials can be produced by placing granulated material of approximately uniform size into a molding box where the granulated material is swelled. Thereafter highly heated gas is blown through the mass until a ceramically binding condition of the surfaces of the granulated parts is reached and until the swelling process is introduced. In such a process, the granulated parts are, as a rule, inflexibly supported to permit expansion into the free spaces where the particles are united to form a body of ceramically bound granulated parts.
However, in the known lightweight construction materials, the final product comprises a grainy structure, i.e., a structure where visible phase interfaces remain. Furthermore, the pore structure in the finished product is not homogeneous with respect to the size and distribution of the pores so that the lightweight construction material does not have isotropic properties, particularly with regard to thermal conductivity and strength. In addition, the known construction materials have a high water adsorptive capacity and the processes for making same are technologically complicated and expensive.
It has been attempted to swell suitable massive bodies, e.g., briquettes and continuous long pieces of clay-containing material, in a furnace. In this case, the swelled material separates from the unswelled material, falls onto the bottom of the furnace and is withdrawn from there. A homogeneous isotropic construction material with a low water absorptive capacity cannot be produced in this manner either.
In addition to the clay-mineral products, construction and insulating materials made of foamed glasses are known. In contrast to conventional clay-mineral insulation materials, foamed glass does not absorb water and has a diffusion resistance factor which is practically infinite. Such foamed glass products are made by mixing ground glass with a foaming agent and filling the admixture into steel molds. Foaming is induced in a tunnel kiln or compartment kiln and the foamed product is then cooled. As a rule, carbon or an organic compound decomposable to carbon at a temperature below the cell formation temperature are utilized as foaming agents. The foamed glass is practically free from crystals. However, an essential disadvantage of foamed glass lies in its low strength and its low compatibility with mortar. Additionally, when foamed glass porous structure is damaged there is evolved undesirable odors previously trapped in the closed pores.
Accordingly, there still remains a need for a lightweight ceramic material which has the desirable properties of both clay and glass insulating and light construction materials.